fe) ENTOMOLOGICAL NEWS. [Feb., 14 
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sketches applied. This correspondence, which will be referred 
to again, clearly indicates that in recent literature two or more 
species of dragon flies have been confused under the name of 
pallidus. 
I have no doubt of the existence in the genus Gomphus, as 
generally used, of several subgroups, along the lines indicated 
by de Selys and Professor Needham. As soon as possible 
it will be convenient to use these subgroups as genera. But 
before this can be done an exhaustive study of the approxi- 
mately seventy species involved will be necessary. At pres- 
ent no one can use these group names intelligently. These 
groups have been defined by Professor Needham, so far as 
imagoes go, in terms not used or emphasized by de Selys, 
whose groups were based largely on thoracic pattern, though 
the resultant groupings, in the two cases, have much in com- 
mon. For example de Selys’ Group 5 includes pallidus (and 
villosipes), lividus, spicatus, minutus and exilis. Arigomphus, 
as used by Needham, includes ‘pallidus, villosipes, spicatus and 
other species not known to de Selys in 1858, the date of the 
Monographie. Lividus and e-xilis are placed in another group 
by Needham, who has not discussed minutus. 
As stated above the groups require accurate definition. So 
far as de Selys goes, spicatus and e-rilis, at least, should not be 
associated with pallidus; and in Needham’s arrangement it is 
certainly a mistake to separate evilis and spicatus, for example. 
Arigomphus is defined (Aquatic Insects Adirondacks, p. 447-8) 
as having two cells between the base of veins At and A2 at 
their origin. Five males and one female of villosipes, selected 
at random, all have a single cell. Three males of cornutus, 
which is an Arigomphus, have two wings with one cell, and 
four wings with two. This character is tabulated below for 
the material discussed in this paper. To the shape of the apex 
of abdominal segment 8 some importance may attach, but the 
character is difficult of accurate definition (see Fig. 8, and ex- 
planation). As to the hind femora in the two sexes, I have 
examined thirty species of which I have both sexes, and the 
femora are different in the sexes in all of them. In the males 
